I agree Teegy. Dog food companies should offer the vets a better solution. I still can't figure out the dog food industry. Some dogs eat foods that are considered crap and they actually thrive on it. I guess it's like humans, researchers are always changing what they claim is healthy for us.
We just have to remember there is no perfect dog food. Regardless of the food prescribed no dog should suffer for a week or longer with watery poo. That is entirely too long . Another vet's opinion may be in order.